Portable communication device

ABSTRACT

A portable communication device is disclosed comprising a front face ( 3 ) having a plurality of openings therein, and an array ( 6 ) of keys. Each key has a switch actuator, a switching element, and coupling means. The switch actuator has an upper surface bounded by side walls, and the switch actuator of each key of the array ( 6 ) protrudes from one of the plurality of openings to provide its upper surface for tactile actuation by a user and is physically discrete from the others. The coupling means couples the tactile actuation of the upper surface by a user to the switching element.

[0001] The present invention relates to a communication device having animproved keypad.

[0002] The keys of a current communication device generally have threecomponent parts. The first part is an array of key domes generallyprovided on a flexible substrate. Each dome can be depressed to actuatea switch of the phones electronics. A plastic, one-piece key pad is laidover the array of key domes. The key pad has, on the surface exposed tothe user, an array of depressible protrusions interconnected by aplastic web and corresponding protrusion on the reverse side. The keypad is held in the correct place using a cover. When an depressibleprotrusion is depressed, the corresponding protrusion on the reverseside depresses the key dome and actuates a switch.

[0003] One problem that arises with such key pads when a depressibleprotrusion of a key pad is incorrectly depressed. If it is depressed atthe wrong place or the wrong angle, the corresponding protrusion may notdepress the key dome or may affect the operation of an adjacent key. Itmay therefore be important to ensure that a depressible protrusion canbe depressed correctly.

[0004] This problem may be exacerbated when one tries to design a keypad in which the keys have some “play”, that is there is a real sense ofmovement and actuation when a key is depressed. The further a key has totravel to depress the key dome, the more likely it becomes that a smallerror in keying will result in a failure in switching.

[0005] The problem may be further exacerbated by the current drivetowards miniaturisation. As keys become smaller and smaller it becomesmore and more difficult to accurately depress the key.

[0006] It would therefore be desirable to generally improve the keys ofa communication device by addressing the aforementioned problems.

[0007] According to one aspect of the present invention, there isprovided a portable communication device comprising a front face havinga plurality of openings therein, and an array of keys, each keycomprising a switch actuator and a switching element, wherein eachswitch actuator protrudes from one of the plurality of openings toprovide its upper surface for tactile actuation by a user, and a couplerfor coupling the tactile actuation of the upper surface by a user to theswitching element, wherein the coupler comprises a shaft extending fromthe switch actuator and a first bearing around the shaft, the firstbearing being a jewelled bearing allowing for longitudinal movement ofthe switch actuator with respect to the first bearing.

[0008] Preferably, the first bearing is hard wearing so that it will beable to handle multiple operations over a substantial period of say 20years. Also, it will provide a good accuracy of fit for the shaft. In apreferred embodiment, the first bearing comprises corundum gemstone, forinstance ruby. A ruby bearing is attractive, which is of particularbenefit when the device has a substantially transparent front face(comprising sapphire, for example), and the user can see this jewel.Other jewelled bearings may be used.

[0009] Preferably, the coupling means further comprises first and secondbearings for supporting the shaft, as such bearings will improve thepositioning of the key during travel. That is, the bearings will definea path along which the shaft can move. The further the first and secondbearings are spaced apart, the straighter the key is held when it isoperated, thereby further improving the likelihood of avoidance ofcontact with neighbouring switch actuators and potentially reducing thespace required between keys to prevent such contact. Maximum spacing isprovided in a preferred embodiment, by extending the shaft through theswitching element and locating the first bearing on one side of theswitching element, between the switch actuator and the switchingelement, and locating the second bearing on the other side.

[0010] Optionally, the second bearing provides a shock absorbing effectby being resilient. The bearing may, for example, be a PFTE bearing.

[0011] Preferably the switch actuators are physically discrete orseparate from other keys. In this case, the operation of one switchactuator does not interfere with the operation of another switchactuator. Consequently, operation of the one key does not interfere withoperation of another. Furthermore, it may enable the switch actuators ofadjacent keys to be more closely spaced.

[0012] Preferably, the switching elements are also physically discrete,so as to reduce the risk of an inaccurate operation of one switchelement affecting the operation of another.

[0013] The switching element may comprise a contact and a mechanismresponsive to the coupling means for bringing the contact into and outof contact with a corresponding contact of the device. In oneembodiment, the switching element comprises a spring plate, the springplate having a fixed end, a free end and a contact for contacting with acorresponding contact of the device provided towards the free end. Italso comprises a flexed tongue between its fixed and free ends. In sucha device, the coupling means is arranged to couple the tactile actuationof the upper surface by a user towards the fixed end of the springplate.

[0014] The array may comprise a row of keys in which the spring platesof first and second adjacent keys in the row are perpendicular to eachother. This is of particular advantage in situations where it is notphysically possible to align the spring plates with the switchactuators, for example because the spring plates are longer than abuttedswitch actuators and/or because the key shaft aperture of the springplate is off-centre, such that the distance from the shaft to one end ofthe spring plate is greater than the corresponding distance from theshaft to one end of the switch actuator.

[0015] In a preferred embodiment, there are more than two keys in a row,and in this case the spring plates of alternate keys are positionedidentically. That is, they are in parallel and around the same way.Where there is more than one row, for example, in a 3×4 alphanumeric keyarray, the spring plates of keys in each column are positionedidentically.

[0016] The key array of the device may comprise one or more rows ofkeys, each row of keys protruding through a respective single opening inthe front face.

[0017] Preferably, the keys in each row are contiguous. That is, theyare in close proximity. This eliminates the need for the front plate toinclude a composite or other filler material between the keys, therebysimplifying both manufacture and the overall appearance of the device.This advantage is further realised when the contiguous keys extend rightacross the front face, from one side of the front face to the other, sothat no material is required between the outer keys and the edge of thefront face. For example, if the device comprises a bezel surrounding thefront face, the keys will extend across the front face, so that theouter keys are in close proximity with the edge of the bezel.

[0018] In a preferred embodiment, the contiguous keys protrude through asingle V shaped opening in the front face.

[0019] If the contiguous keys comprise a central key, a left key to theleft of the central key and a right key to the right of the central key,the central key is generally contiguous with the left and right keys,whereas the left key is generally contiguous with only the central keyand the left key with only the central key. The central key has a key oneach side and it is important that it does not affect the other keyswhen actuated. It is therefore particularly advantageous to have keyswhich are “sandwiched” between other keys modified to facilitate theircorrect actuation.

[0020] It is of benefit to the user if one of said plurality of keys hasa vertex, in the boundary of its upper surface, as the vertex allows auser to determine the correct location at which the key is to beactuated. The vertex provides both a visual and tactile indication ofthe correct place for actuation.

[0021] The vertex is generally formed where two portions of a side wallmeet at a point. The vertex may feel like a pointed or V shapedprotrusion, where the angle formed at the interior of the key betweentwo side wall portions is less than 180 degrees. The vertex may feellike a V shaped recess to the side wall where the angle formed at theinterior of the key between the two side wall portions is more than 180degrees. The key may be V-shaped having two vertexes. The or each vertexprovides a means for differentiating one key both visually and by touchfrom other keys and thereby provides the user with an origin fororientation.

[0022] The switch actuators may be one type of individual elements ofthe device which may be customisable, so that the commissioner maycreate their own potentially unique personalised item. The switchactuators may comprise metal—precious (such as gold, platinum, orsilver), or non-precious such as stainless steel. They may also, oralternatively, comprise surface decoration, such as encrustation, aveneer, an image, a colour or engraving, for example. Typical switchactuator configuration may be the addition of a jewel—such as a setstone or diamond encrustation.

[0023] Embodiments of the invention will now be described in more detailwith reference to FIGS. 1 to 25 of the accompanying drawings of which:

[0024]FIG. 1 is a perspective view of a communication device showing oneembodiment of the invention;

[0025]FIG. 2 shows front, rear, sides and top views of the communicationdevice of FIG. 1;

[0026]FIG. 3 is a schematic representation of a communication devicesuitable for embodiments of the present invention;

[0027]FIG. 4 is an exploded view of the face of a communication deviceof one embodiment of the invention without keys;

[0028]FIG. 5 is a view of one layer of a light guide;

[0029]FIGS. 6a and 6 b are sections through the communication device ofFIG. 1 in the display region;

[0030]FIG. 7 is a perspective view of a side frame element and locatedrails for constructing a casing

[0031]FIG. 8 is a perspective view of the rear of the device with thebattery cover removed;

[0032]FIGS. 9a and 9 b are sections through the communication device ofFIG. 1 in the battery region;

[0033]FIG. 10 is a perspective view of the rear of the device with thebattery cover in place;

[0034]FIGS. 11a and 11 b are sections showing other embodiments of theinvention;

[0035]FIG. 12 is a perspective view of part of the input region of thedevice illustrating the location of legends associated with keys;

[0036]FIG. 13 a longitudinal section through the communication device;

[0037]FIG. 14 is a schematic section through the light guideillustrating the surfaces available for carrying the legends;

[0038]FIGS. 15 and 16 are perspective views of a partially constructedinput region of the device;

[0039]FIG. 17 is a perspective view of keys of the device includingtheir actuation mechanisms;

[0040]FIG. 18 illustrates some of the keys illustrated in FIG. 17, withthe switch actuators removed;

[0041]FIGS. 19a and 19 b are front and rear perspective views of theouter shell of a bezel respectively;

[0042]FIGS. 20a and 20 b are a graph showing force against distance fora key such as that illustrated in FIGS. 17 and 18, and a conventionalkey using a dome respectively;

[0043]FIG. 21 is a bottom plan view of the device of FIG. 1 (with thechin face protector omitted);

[0044]FIG. 22 shows a key arrangement according to an alternativeembodiment of the present invention; and

[0045] FIGS. 23 to 25 show front face protectors according toalternative embodiments of the present invention.

[0046] Embodiments of the invention will be described in greater detailbelow with exemplary materials being given for some specific orindividual elements of the device. Where a material or veneer isdiscussed in relation to an element, the particular character of theelement described is one of many or several that may be provided asoptions to a party commissioning a personalised device in accordancewith the invention. In addition the exact material or surface decorationof the element could be individually commissioned.

[0047] The embodiment illustrated in FIG. 1 is a communication device 1with a precious retainable casing 2. The casing 2 of the device has beendesigned to be customisable to individual taste with precious materials.To enable individual devices to be created, the number of external partsthat the casing is formed from is relatively large in contrast toexisting communication devices.

[0048] The casing 2 has an optically permeable front face 3 providing aseamless transition from a display region 4 to an input region 5 thatincludes a key array 6. The key array 6 includes a first group ofalphanumeric keys 7, for entering telephone numbers, writing textmessages (SMS), writing names (associated with phone numbers), etc. Eachof the twelve alphanumeric keys 7 is provided with a figure “0-9” or asign “#” or “*”, respectively. In an alpha mode each key is associatedwith a number of letters and special signs used in text editing. The keyarray 6 additionally comprises two soft keys 8, 9, two call handlingkeys 10, 11, two scroll keys 12, and an on/off key 13.

[0049] The functionality of the soft keys 8, 9 may depend on the stateof the communication device and position within the menu accessed usingthe scroll keys 12. The current functionality of the soft keys 8, 9 canbe shown in separate fields in the display region 4 just above therespective keys 8, 9.

[0050] The two call handling keys 10, 11 are used for establishing acall or a conference call, terminating a call or rejecting an incomingcall.

[0051] The two direction keys or scroll keys 12, in the handsetillustrated are placed centrally on the front surface of thecommunication device between the display region 4 and the group ofalphanumeric keys 7 perform a scrolling function.

[0052] The seamless face 3 is formed from an optically seamless lightguide 14 providing light to illuminate the display region 4 and keylegends 15 located on the light guide 14 and associated with individualkeys of the key array 6.

[0053] The front face 3 is overlaid with a pillow 16 providing apertures17 to channel sound from a loud speaker 18 and providing an appropriatefeel for an element of the device that will be located close to theuser's ear. The front face 3 is surrounded by a bezel 19 that can bemade from a precious metal. This acts to protect the edges of the lightguide 14 and can help in some embodiments in securing the elements ofthe casing 2 together.

[0054] The keys of the key array in this particular embodiment arearranged to provide particular sensory guidance to the user. Aspects ofthe design also allow the light guide 14 to be made from a wide range ofmaterials including those that are brittle and so need to be carefullyhandled and protected from shattering.

[0055] The casing 2 is formed from the front face 3 surrounded by thebezel 19, a side frame 20 and a back cover 21. The interface between theside frame 20 and the bezel 19 and the side frame 20 and the rear cover21 are shielded by rails 22, 23 in this embodiment. The rails 22, 23hide raw edges from view and exposure to ensure that the device 1 isboth long lasting and elegant. The construction of the casing 2 enablesthe casing 2 to be opened with ease to update the engine 24 inside whendesired. The casing 2 is also designed to allow the device toaccommodate different sized and shaped engines 24, which may benecessary through its life.

[0056] Other elements of the design will be discussed in greater detailwith reference to the later drawings. By way of introduction, the devicewill be briefly discussed with reference to its functional elements.

[0057] The communication device 1 includes the key array 6, a display25, an antenna 26, an ear piece speaker 18, a polyphonic speaker 27, anda microphone 28. The communication device 1 is adapted for communicationvia a wireless telecommunication network, e.g. a wireless network.However, the communication device could also have been designed for acordless network. FIG. 3 shows schematically and functionally elementsof the communication device 1. The microphone 28 records the user'sspeech, and the analogue signals formed thereby are A/D converted by anA/D converter before the speech is encoded in an audio part 29. Theencoded speech signal is transferred to processor 30. The processor 30may support software in the phone. The processor 30 also forms theinterface to peripheral units of the apparatus. These may include aRandom Access Memory (RAM) 31 and a Flash Read Only Memory (ROM) 32, aSIM card 33, the display 25, and the key array 6, and perhaps a browserapplication 34, and a location module 35.

[0058] The browser application 34 can be used to request and receiveinformation from the Internet. The location module 35 enables theterminal 1 to determine its current position.

[0059] The processor 30 communicates with a transceiver 36, e.g. acircuit, which is adapted to send and receive messages in atelecommunication network. The telecommunications network may be a GSMor W-CDMA network, but the invention may also be applied in connectionwith any other network, including but not limited to other kinds ofwireless networks and various forms of cordless phone systems or in dualband phones accessing sets of these systems or networks. The audio part29 speech-decodes the signal, which is transferred from the processor 30to the earpiece 18 via a D/A converter.

[0060] The display 25 may form a permanent part of the casing or, toincrease the potential for upgrading the engine throughout the life ofthe casing it may be a module that can be replaced to, for example,account for the inevitable improvements in graphics that may occur.

[0061] As discussed above, the front face 3 is optically permeable andacts as a light guide. The seamless light guide, passing light over thedisplay region 4 as well as providing light to illuminate the keylegends 15 reduces the number of lighting elements required toilluminate the device and provides a seamless transition from one areaof the front of the device to another. By using this technique fordelivering light and also allowing the light guide 14 to form the frontsurface of the device 1 as in the embodiment disclosed, the device isvisually striking, there being no visible transition from the displayregion 4 to the input region 5 where the key array 6 is located.

[0062] The embodiment illustrated in FIG. 1 has a light permeable frontface 3 that can be formed from sapphire or a similar precious stone. Assoon as a mineral such as sapphire is used in place of other moreflexible light permeable materials such as plastics, additional problemsare introduced associated with the character of the material. Indesigning a durable device having, for example, a brittle material for afront piece 3 there are many difficulties. In one manifestation of theembodiment illustrated in FIGS. 1, 2 and 4 to 6, the light guide 14 isan optically seamless composite layer. As can be seen most clearly inFIG. 4, a plastics layer 37 that may be formed from Perspex or othertransparent and/or translucent materials runs the entire length of thefront face 3. There is a cut-out 38 for accommodating the ear piecespeaker 18 that is optimised for use close to the ear. There is anothercut-out accommodating a light pipe diffuser 39. This is located underthe pillow 16 and extends across the width of the device 1. By placingthe light pipe 39 under the pillow 16, a bright area on the front faceis avoided and the light visible in the light guide will be diffused.LEDs 40, 41 are located at each side of the device at each end of thepipe 39. Light from the LEDs 40, 41 is channelled through the pipe 39and diffused. The light pipe 39 is coated with reflective material sothat light is channelled through the surface 42 that runs along the topof the LCD display 25. The diffused light is accordingly channelled intoand along the major axis of the light guide 14 to provide substantiallyuniform lighting for the LCD 25.

[0063] In this way light is pumped into the light guide 14 along themajor axis from above the LCD 25. The light from the light pipe 39illuminates the display region 4 and provides lighting for the inputregion 5. As illustrated in FIG. 15, additional LEDs 67 or otherlighting elements are positioned along the edges or the Perspex layer orsheet 37 in the input region 5 to further illuminate the legends 15 forthe keys of the array 6. The surface of extending portions 78 of thePerspex layer or sheet 37 is shaped to channel light from adjacent topfiring LEDs 67 or the like towards the upper surface of the main portionof the layer or sheet 37. This assists in providing substantiallyuniform lighting for the input region. The additional LEDs 67 or thelike are shielded from view by the bezel 19 to avoid light spots beingvisible and encouraging a uniform diffuse light across the light guide.

[0064] The LCD 25 itself is mounted on a board 46 and bonded to the rearsurface of the Perspex sheet 37 with an energy absorbing adhesive sheet45. Using this technique and ensuring that there are no air gaps betweenthe front of the LCD 25 and the Perspex sheet 37, provides a robustsolution for mounting the LCD 25. The surface of the LCD 25 that isdelicate and generally needs a protective layer distanced from it isprotected by the Perspex layer 37 adhered to one of its faces. Thedrivers 44 for the LCD 25 can be seen in FIG. 5.

[0065] In the embodiment illustrated the Perspex layer 37 includesapertures 48 for locating individual keys and allowing the key shafts 49to travel to make contact with a printed circuit board 50 located withinthe casing 2 to register user input. An independently inventive keylayout, suitable for use with the general concept discussed will bedescribed in greater detail below. As the key layout is likely to be oneof the most enduring elements of the design, it has been designed withfuture requirements for the casing in mind. The skilled man will beaware that modifications to the key arrangement can be made while stillproviding the flexibility to accommodate future engine requirements. Forexample, a joystick, or similar rotational device or multidirectionalkey could be utilised for input as could other input mechanismstraditionally used on laptop computers.

[0066] As can be seen most clearly from FIG. 3, the second layer of thecomposite light guide 51 is made in a number of sections 52-58. This isto allow for the choice of brittle materials to be used for the secondlayer 51. Sapphire has properties including its scratch resistance andoptical clarity that make it suitable for use in this context althoughthe material of this element is selectable a ceramic material could beutilised in this arrangement. Other suitable materials are glass andother minerals and precious and semi precious stones. When a transparentmaterial such as sapphire is used, however, the light guide provides anexternal surface to the device. Arrangements for the second layersimilar to those disclosed in concept in the illustrated embodiment arenot necessary when the materials are not brittle. Alternativearrangements will, however, be apparent to the skilled man foraccommodating brittle materials in this context.

[0067] As mentioned above sapphire is brittle. When considering how tointroduce such a material into a casing 2 that is to be long lasting anddurable, problems arise. This is particularly the case when the device 1will inevitably be subjected to knocks and is likely to be dropped manytimes in its long existence. In the embodiment described, the sapphireis formed in individual sections 52-58 for ease of manufacture. Each ofthe pieces is adhered to the Perspex layer 37 using a UV curing adhesivebased on hybrid acrylic technology. In order to increase the durabilityof the composite light guide 14 and strengthen it against damage, thesections 52-58 are adhered to a more flexible Perspex layer 37 leavinggaps 59 extending across the entire width. These gaps 59 act as hingesto allow the composite layer 14 to be relatively flexible along itsmajor axis. In the embodiment illustrated, the layout of the key array 6has been designed with this in mind. The alpha numeric keys 7 arearranged in groups of three extending across the whole width of thesecond layer of the composite 51. The function keys or soft key 8, 9 arealso arranged in two groups of three. The soft keys 8, 9 and the topscroll key 12 a follows the line of the alpha numeric keys 7. The callhandling keys 10, 11 and the bottom scroll key 12 b which is displacedfrom the line of the others defines the lower edge of one of theelements 57 and the upper edge of another of the elements 56. This makesthe second row of keys 10, 11, 12 b distinctive whilst still avoidingproblems in manufacture of the elements 52-58. The specific key array 6illustrated has other properties and advantages that will be discussedlater.

[0068] Although the embodiment described is designed with a brittlematerial such as sapphire in mind, the resultant arrangement could beformed from any number of other materials including plastics thatprovide the required optical characteristics. Similarly different keyarrangements could be used without departing from individually inventiveconcepts that are disclosed.

[0069] When using a brittle material for a front face light guide 14problems are also encountered when connecting the front face 3 to therest of the casing elements. In the illustrated embodiment the edges ofthe brittle elements 52-58 are protected by the bezel 19 that sitsaround the whole of the face. The bezel 19, in this embodiment, isformed from a bezel support 60 overlaid with a 0.5 mm thick metal sheet,the bezel cover 61. The metal sheet 61 is bonded to the bezel support60, that may be formed from plastic, with an adhesive such as a two partepoxy adhesive or a two part acrylic adhesive. As the metal sheet 61 isrelatively thin this keeps the weight of the casing 2 down and alsoallows relatively precious metals such as titanium or gold to be used atrelatively lower cost. The bezel 19 could, however, be a single partand/or be formed from a single material for example titanium.

[0070] The transparent face 3 in this particular embodiment is securelyheld in place by a robust mechanism. The Perspex layer 37 to which theelements 52-58 are bonded extends beyond the area covered by theelements to provide a lip or edge 62 around the whole of the compositelight guide 14. This edge 62 is used to secure the front face 3 inposition as it is tucked under the bezel 19 that defines the perimeterof the front face and squeezed between the bezel 19 and the side frame20.

[0071] As can be seen in FIG. 1, the bezel 19 is punctuated with frontface protectors 63 whose function will be described in more detaillater. These front face protectors 63, in this particular embodimentplay a role in holding the casing elements together.

[0072] The front face protectors 63 have a tip part 64 that extends overthe bezel 19 and a shaft 65 that passes through the bezel 19 and intothe plastic side frame 20. The shaft 65 may be tightened onto the frame20 using a nut 95. In this case the nut stops the front face protectorsfrom falling out of the device. In one embodiment the shafts 65 arescrewed into the tips 64 at one end and into the side frame element 20at the other although other manners of connection could be employed. Theshaft 65 and tip 64 could also be one piece rather than two. The bezel19 and the Perspex layer 37 of the transparent face 2 are captured bythe front face protector 63 and side frame element 20 as can be seen inFIG. 9b. The front face protectors 63 accordingly grip the transparentface 3 securely between the side frame 20 and the bezel 19. The frontface protectors 63 are only located next to the key array 6. In order tosecure the transparent face 3 around its perimeter additional screws 66are added to draw the bezel 19 towards the side frame 20 and squeeze thetransparent face 3 in place. In one embodiment, the screws 66 threadthrough the side frame 20 and tap into the bezel support 60. Once thebezel support 60 is secured to the side frame 20 the outer shell 61 ofthe bezel 19 can be adhered to the support 60 to hide the tapped screwends 66.

[0073] As can be seen in the figures, although the more flexibletransparent substrate 37 is overlaid by the bezel 19 secured in positionby the front face protectors 63 and other connectors, the sapphire ismaintained spaced from the bezel 19 so that it is protected fromchipping or other damage as a result of contact. The edges of thesapphire elements do not protrude above the edge of the bezel 19 toprovide further protection for the more vulnerable edges. In thearrangement described, the transparent face 3 is gripped in positionbetween the bezel 19 and the side frame 20. The more flexible substrate37 could, however receive screws or other fasteners to located itrelative to the other frame members without damaging the more brittlesapphire layer. The choice of material for the bezel is one open toselection. Precious metals including gold, platinum, silver, steelamongst others would be suitable. The same applies to the material ofthe front face protectors. Both these elements and others that theskilled man will realise are suitable could be encrusted with preciousor semi precious stones such as sapphires, rubies, emeralds and diamondsamongst others. Other crystals or minerals or other materials andveneers could also be utilised.

[0074] To reduce the ingress of dirt or fluids a sealant 69 is locatedbetween the bezel 19 and the transparent face 3. One way in which thiscan be introduced is to paint a seal on the underside of the bezel 19which when dry is compressed between the transparent light guide 14 andthe bezel 19 when the bezel 19 and the side frame 20 are pulledtogether.

[0075] As can be seen in FIG. 6 or 9, a first rail 22 is located in theinterface between the side frame element 20 and the front face 3. Therail 22 hides the discontinuity between the parts from sight andprotects vulnerable edges to enhance the durability of the device 1. Therail 22 may be a stamped metal piece ‘T’ shaped in section extendingaround the perimeter of the side frame 20. The stem of the ‘T’ 68 istrapped between the side frame member 20 and the bezel 19 as these twopieces are drawn together on assembly. The stem of the T has apertures70 that sit over corresponding projections 71 on the side frame 20member to prevent it from being withdrawn from between the two partswhen in position. The top of the T acts as a carrier plate to which anadditional extruded piece 72 is soldered or otherwise adhered to providea seamless finish. The stem could instead be formed from a plasticsmaterial.

[0076] The side frame member 20 in this particular embodiment is aplastic support 73 with an exterior cover 74. The cover 74 may again bea metal sheet formed, for example, from a precious metal or perhaps awood veneer or another layer such as leather or other skin. The bondingagent most suitable for adhering the layer to the plastic frame member73 will differ depending upon the materials that need to be adhered. Formetal to plastic a suitable adhesive is a 2 part epoxy resin or 2 partacrylic adhesive. For metal to metal the adhesive would be a reactivepolyurethane film or a two part epoxy resin. Similarly the back cover 21in this embodiment may have a plastic frame and be covered with forexample a leather, wood or perhaps metal veneer. With the flexibleveneer materials such as leather, it is preferable for the material tobe taut on the frame. This is achieved during the veneering processusing conventional techniques.

[0077] The transparent face 3 provides a seamless transition between thedisplay 4 and the input regions 5. In the display region 4, the LCD 25is located behind the transparent face 3 and in the input region 5 thekey mechanism 75 lies behind it. In one embodiment described, the keymechanism 75 can be seen through the front face 3. However, in otherembodiments the inner surface 76 of the Perspex substrate 37 may becoated with an opaque material to prevent the inside of the device beingseen. Alternative methods of obscuring the inner workings of the devicefrom view such as introducing additional opaque layers or obscuring theview in other ways will be apparent to the skilled man.

[0078] For embodiments where, for example, the key operating mechanism75 can be viewed through the front face 3, it may be desirable toobscure the PCB 50 from view.

[0079] The constructed casing 2 provides a housing for the printedcircuit board 50 holding the engine components 24, and a battery 79.When the device 1 is a radio telephone, the casing 2 may also provide aSIM card holder 80 to accommodate a SIM card 81. For operation undersome radio protocols this will clearly not be necessary.

[0080] Returning briefly to the front of the device, located above thedisplay region 4 is the pillow 16 so named because it designed for theuser to rest his or her ear against when making a telephone call. Thepillow 16 overlays the ear piece 18 of the device. As describedpreviously there is a cut-out in the Perspex substrate 37 of the lightguide 14 to accommodate the ear piece 18, the pillow 16, in theillustrated embodiment is adhered to the Perspex substrate 37 coveringthe ear piece 18. The pillow 16 provides suitable apertures 17 tochannel sound to the user. The characteristics of pillow 16 both interms of the material and surface decoration may be selectable by acommissioning party.

[0081] The Perspex and sapphire light guide 14 is relatively cold to thetouch, the material of the pillow 16 can be chosen to be a material thatis inherently warmer to the touch and less prone to marking than atransparent shiny surface. Materials that are thought to be particularlysuitable are wood and leather veneers. The shape of the pillow 16obscures part of the LCD 25, providing opposing triangular sections 82,83 that are used to indicate battery capacity and signal strengthrespectively.

[0082] To complete the structure, the casing 2 has a rear cover 21 andinternal compartments 84, 85 suitable for retaining the engine 24 thebattery 79 and in this embodiment a SIM card 81. The device illustrated,in common with many other radio telephones, advantageously allows accessto the battery compartment 85 as the battery 79 may periodically needreplacement. In order for the engine 24 to be protected during thisactivity, the battery 79 is retained in a compartment providingconnectors to the engine 24. Along side the battery compartment 85 inthis embodiment is the SIM card holder 80. Under protocols where a SIMcard 81 is used to hold subscription information, the user may wish toremove the SIM card 81. For this reason it is convenient for the backcover 21 to be removable to expose both the battery 79 and the SIM card81. The battery compartment 85 and SIM card holder 80 are provided by aninternal casing element 87 that is secured to the side frame 20. Thismay be formed from plastic or one of many other suitable materials. Inone embodiment the compartments are formed from stamped metal sheet.Titanium and aluminium are two from the numerous suitable materials.

[0083] The battery contacts 90 protrude into the battery cavity 85 toprovide a simple way of connecting the battery 79 to the engine 24. Thebattery connection will typically be have a power connector 91, a ground92 and two signal connectors 93, 94.

[0084] There are several problems associated with battery connections.One is keeping the resistance of the connector to a reasonable level asany resistance reduces the efficiency of the battery 85. Another ismaintaining connection with the battery at all times. When the batterydisconnects from the engine of a device, in many cases default settingswill be re-entered and the user will be required to take some action inorder to continue use of the device in the manner in use before thedisconnection. This is at best irritating to the user and could resultin the present operation being aborted. This may be particularlyproblematic if the device is a radio telephone and a call is dropped asa result of the lost battery connection.

[0085] Harmonic resonance in the connectors is a surprisingly frequentoccurrence and can happen for example when a device is tapped or whentravelling in a vehicle or other environment where it will encountervibrations. This can cause a single one of the power or ground batteryconnectors to momentarily break contact with the battery 79 which issufficient to cause a break in the power supply.

[0086] In the embodiment illustrated, the power 91 a,b,c and ground 92a,b,c connectors are divided into three. This reduces the resistancebetween the battery 79 and the engine 24 as the leads are in parallel,it also reduces the chance of power being lost to the engine 24 as aresult of a harmonic resonance frequency of the connector being reachedas at all times there is likely to be at least part of each three partconnector completing the circuit between the engine 24 and the battery79.

[0087] The casing 2 is completed by assembling the back cover 21 to theside frame 20. In the illustrated embodiment, the back cover 21 isformed from three pieces 96, 97, 98. A first piece 96 overlays theantenna location. In this embodiment it provides an aperture 99 in whichthe polyphonic speaker 27 is located to provide for polyphonic sound.This additional speaker 27 has not been optimised for use in closeproximity to the ear as has the speaker 18 located beneath the pillow16. This allows it to be more effective as a handsfree speaker andenables a greater range of ring tones to be utilised. As the first piece96 also covers the antenna its dielectric constant is relevant.

[0088] In a device of this type where the casing 2 is to survivegenerations of engines 24, the materials from which is formed areimportant. They should be hard wearing and durable, retaining theirattributes for years longer than is currently required. For this reasonceramics have been considered as an option for the back cover 21 forsome embodiments of the invention. Other materials already discussedsuch as metals or precious metals or veneers would also be possible.With ceramics, however, despite having many desirable characteristics,for locations near an antenna relevant for devices containing such anelement, the dielectric constant of the material interferes with thedesired transmission pattern.

[0089] To provide many of their desirable characteristics without thedielectric constant becoming too high, the rear cover piece 96 can beformed from a material with a lower dielectric constant with a suitabledepth of layer deposited on it. This technique and suggested materialscould be used for other elements of the casing.

[0090] The rear casing element 96 covering the antenna is again screwedto the side frame element 20 and in the process captures the second rail23 similar in construction to the first rail 22 between the side frame20 and the back cover 21. Again the rail 23 is provided with apertures70 that are positioned over corresponding projections 71 on the sideframe 20 to more securely hold the rail 23 in position when the backcover 21 is attached.

[0091] A second rear casing element 97 covers the battery compartment 85and the SIM card holder 80. This element is releasably secured to theother casing elements using screws 99 to allow relatively easy access tothe SIM card 81 and battery 79. In a preferred embodiment a quarter turnof a screw 100 releases the cover element 97 to allow it to be removed.The same action can disconnect the battery 79 to allow the SIM card 81to be removed.

[0092] The second rear casing element 97 is attached to the side frame20 in a similar manner to that described in relation to the first rearcasing element.

[0093] The third element of the rear casing 98 covers the polyphonicspeaker 27. This may be only relatively thin and formed from a preciousmaterial such as gold. It will be provided with a suitable aperture 102to channel sound from the polyphonic speaker 27 that may be use in handsfree mode and for providing an audible ring tone.

[0094] In the embodiment described the front 3 and rear casing elements96, 97, 98 are secured to the side frame 20. A silicon sealant 69similar to that provided on the underside of the bezel 19 may beextruded around the inside of the back cover 21 to prevent unwantedingress of dirt and fluid.

[0095] The skilled man will realise that the number of parts and themanner in which they are connected can be changed without departing fromthe several inventive concepts described. For example, in otherembodiments the casing may be held together using other techniques andin other ways.

[0096] As well as obscuring exposed edges, the rails 22, 23 provideadditional elements for customisation as they can be formed from avariety of different materials, in particular different types ofprecious metal for example gold or platinum as discussed previously inrelation to the bezel. The material for the entire ‘T’ shaped piece orthe extruded element could be a precious metal. They also act to protectvulnerable edges of veneered frames from exposure to potentiallydamaging forces. In doing this unsightly edges are obscured from view.This provides quality and durability in keeping with the overall conceptof a retainable casing for a communications device. Regardless of thematerial of the veneer, this is a convenient arrangement for securingall the elements in place for a durable finish.

[0097] In an alternative embodiment illustrated in FIG. 4b, instead ofproviding rails 22, 23 to protect exposed edges, the adjacent edgesthemselves are turned inward 105, 106 and held in close proximity. Thisarrangement also provides the advantage of protection and keepsunsightly discontinuities from view.

[0098] A casing with an optically permeable front face provides newopportunities. In a particular embodiment, described with reference toFIGS. 12 and 14 legends 15 associated with the keys of the key array 6are located on both the front 37 a and rear 37 b surfaces of the Perspexlayer 37. With communications devices becoming ever more sophisticated,it is common for each key provided to have a number of differentfunctions. It is useful to be able to label visually the differentpossible functions associated with a key. For the alpha numeric keys 7in particular, each key is associated with a single digit and a group ofletters or symbols. Ideally these should be displayed clearly.

[0099] Historically the keys have held the associated legends. Asdevices have become smaller this has, however, becomes more difficult,it being an especial problem to distinguish between the differentlegends for respective modes of operation as the letters and numbers areso small. In the illustrated embodiment, the legends 15 for associatedkeys are located on respective surfaces of the light guide 14 which asthe device is tilted, move together or apart depending upon the anglefrom which they are viewed. This provides a visual distinction betweenthe legends 15 on the different surfaces which can be used todistinguish between the modes of operation. As the front face isoptically permeable, the legends appear to float in or above the device.By spacing the legends along an axis perpendicular to the thirddimension, the thickness of the front face, the front face is given someprominence, thus an additional dimension has been added to the normallyopaque front face.

[0100] In the embodiment illustrated the legends 15 are located on theoutermost and innermost surfaces of the Perspex layer 37 a, 37 b. Thelegends 15 appear to be floating in the light permeable layer. Themanner in which the legend 15 is located on the layer is a matter ofchoice for the skilled man. One method is to print the legend on to thesurface using an etched plate filled with ink. Another way may be byusing PVD (Physical Vapour Deposition) techniques to deposit the inkdirectly onto the Perspex layer. Other techniques for fixing legendscould be used including attaching labels.

[0101] In the embodiment discussed the legends 15 a 15 b are located onopposing surfaces of the Perspex layer 37 a 37 b. This enables a singleelement, the Perspex layer 37, to be printed instead of each of thesapphire or other pieces 52-58. Problems encountered with ink wearingoff when printing techniques are used are also avoided by protecting thesurfaces containing the printing with the second layer. In otherembodiments and to increase the depth of spacing of the legends andhence the separations possible when viewed at different angles it may bedesirable to place the legends on the innermost 37 a and outermostsurfaces 51 a of the composite. In order to fix the legend 15 printed onthe outer surface 51 a where it may encounter wear, a coating or otherprotective layer may be provided over the surface. This may not benecessary if PVD techniques are used to produce the legend 15 as suchtechniques produce a bond between the deposited layer and the substratethat is more hard wearing. In still other embodiments the legend 15could be provided on the underside 51 b of the sapphire elements and onthe innermost layer of the Perspex substrate 37 b. Again by avoiding theexternal surfaces of the transparent layer the problem of wear of thelegends 15 is largely avoided. The outermost legend is protected by thetop layer 51 of the composite light guide 14 and the innermost legend 15is not accessible.

[0102] In sandwiching the legends between two optically permeable layers37, 51 which of the two sandwiching layers carries the legend is largelyimmaterial. The properties of the respective materials, if indeed theyare different, and other factors can be taken into account in decidingwhich layer 37 b, 51 b actually carries the legend. With a compositeoptically permeable substrate, the more layers that are provided, themore visually distinguishable legends can be accommodated. For examplewith two composite layers there are three available planes for legends,with three layers, four planes and so on. If all the legends were placedadjacent a single key, the visual distinction may cause difficulty withlarge numbers of layers being used to distinguish functionalities. Otherembodiments could use the different planes for legends at differentlocations on the device so that one set of keys has a legend in a firstplane, a second set of keys in a second plane and so on.

[0103] To accentuate the illusion of the legends floating, or toincrease the distinction between the two layers, the thickness of theoptically permeable layer between the respective layers carrying thelegends can be increased. In the same way these features can be reducedby decreasing the thickness between the planes carrying the legends.

[0104] The ink or paint can be chosen by the skilled man to provide anumber of effects. The ink may, for example, be required to pearlesce orfluoresce, or be black, white, or one or more of a wide range ofcolours. As the legend is located on a light guide, fluorescent andpearlescent materials enhance the visibility of the legends. The typescript, colour or other character of the legend or element carrying thelegend may be selected by a commissioning party.

[0105] Instead of techniques that add ink or other visible materials tothe surface merely etching the layers may be sufficient to make thelegends visible if the illumination is adequate.

[0106] Embodiments illustrating the location of legends associated withkeys in a light permeable face has been described with reference to theillustrated embodiments in the context of other independently inventivefeatures claimed in copending applications. The skilled man will realisethat many alterations to the specific features disclosed can be madewithout departing from the scope of the invention.

[0107] The skilled man will be aware that the character described abovein relation to specific elements of the device can be mixed and matchedto suit many distinct design options.

[0108] The input region of the device will now be described in moredetail, primarily with regard to FIGS. 9 and 15 to 21.

[0109] The input region 5 comprises a key array 6, as described above.In this embodiment, the key array is made up of a plurality ofindividual keys 713. Each of these individual keys comprises a switchactuator (or key tip) 64 and shaft 49 extending from substantially thecentre of the key tip 64, together with an upper bearing 103, O ring107, circlet 108, spring plate 110 and lower bearing 109 positionedrespectively along the shaft 49 a from the key tip 64. The spring plate110 is supported by a spring plate support 114 provided on the PCB 118.The spring plate comprises a main body, and a tongue 111 formed from asingle piece of sheet metal. The tongue has been formed by stamping aninner portion of the sheet, so that two sides and an end of the tongueare free from the remaining main body of the sheet. The spring platealso has a portion or portions stamped out to provide an aperture forthe key shaft 49 and spring plate support 114. One end 113 of the springplate comprises contacts for contacting respective contact regions onthe PCB. As will be appreciated by a person skilled in the art, a singlecontact could be used for this purpose, but the provision of twocontacts provides greater reliability. The spring plate support 114comprises three members upstanding from the PCB 118. These members mayform part of a unitary structure, or may be separate elements. The firstmember comprises a recess 115 dimensioned to receive one end 112 of thespring plate 110 and hold that end 112 in position. The second member ofthe support 114 comprises a lip 116 extending towards the first member.This lip 116 is provided to restrict the upward movement of the otherend 113 of the spring plate 110. The third member of the support 114comprises a recess 117 for receiving the end of the tongue. This thirdmember is positioned relative to the second member, such that the tongueof the spring plate 110 has to be flexed in order for the end of thetongue to correspond with its recess 117. Optionally, the spring platesupport may comprise a fourth member comprising a lip extending towardsthe second member. In this case, the PCB contact regions are extended tothe surface of this lip, so as to bring them closer to the spring platecontacts. Alternatively the contact region bearing lip may be formed aspart of the second member itself, or eliminated altogether.

[0110] As mentioned above, in the present embodiment, the individualkeys are grouped in threes, their tips extending across the whole widthof the second layer of the composite 51. This facilitates manufacture ofthe brittle elements 52 to 58. The tips of the alphanumeric keys 7, softkeys 8, 9 and top scroll key 12 a are in alignment with those of theother keys in their group. In the remaining group of keys, however, thetip of the bottom scroll key 12 b is displaced from the line of the tipsof the other two keys in its group, namely the call handling keys 10,11. In any event, in each group the edges of adjacent key tipscomplement each other, and are closely spaced. This eliminates the needfor the composite 51, or other filler material, to extend between thekey tips. It also has the advantage of simplifying the overallappearance of the input region of the device to the user. Furtherproperties and advantages of the specific key array 6 will be discussedbelow.

[0111] As can be seen in particular from FIGS. 17 and 18, the springplates 110 and supports 114 of adjacent alphanumeric keys 7 arepositioned perpendicular to each other. This provides a geometricallysimple solution to the problem that the spring plates cannot bepositioned in alignment with the keys themselves. One cause of thisproblem in the embodiment illustrated is that the spring plate of eachouter key is longer than the average length of its corresponding keytip, and this extra length cannot be accommodated elsewhere. This isprimarily because the spring plate of each central key is only minimallysmaller than the average length of the corresponding key tip, and thekeys are closely abutted (there is only a gap of about 0.245 between thekeys) so that there is insufficient space to allow for the extra length.Furthermore, whilst the key shaft 49 of each key is substantiallycentral to the key tip 64, the key shaft aperture of the spring plate110 is off-centre. This exacerbates the problem for the outer keys, andeven results in the spring plate of each centre key not being able to beaccommodated in the space under its corresponding key tip.

[0112] The keys may be constructed, and the input region of the deviceassembled, as follows. Upper bearings are inserted into the apertures 48of the Perspex layer of the device. Ruby bearings are preferablyselected for this purpose, for three main reasons. Firstly, ruby is veryhard wearing, and will thus be able to handle multiple operations of thekeys over a substantial period of time. Secondly, the upper bearings ofthis device are larger in diameter than the corresponding widths of thekey tips, which means that they will be visible in situations in whichthe front face of the device is transparent (e.g. second layer 51 may besapphire). Hence, advantage may be taken of the fact that a ruby is anattractive jewel, which the user will be pleased to see. Thirdly, theuse of a hard material such as ruby will provide greater accuracy of fitof the key in the device, as opposed to using a resilient material, suchas PFTE. Other hard-wearing precious stones such as diamond or sapphiremay be used. The upper bearings 103 allow for longitudinal movement ofthe keys with respect to the first bearing i.e. the shaft of the keymoves in a longitudinal direction with respect to the longitudinal axisof the bearing.

[0113] Lower bearings 109 are provided in a titanium plate which isfixed to the rear of the PCB 118. The inner and outer diameter of thelower bearings 109 are smaller than the upper bearings 103, but theircentres are aligned. They are also preferably made of differentmaterial—the material of the lower bearings having shock absorbingqualities such as PFTE.

[0114] The key shafts 49 are machined, to have a first portion 49 a ofappropriate thickness to pass through the inner diameter of the upperbearings 103 and a second reduced diameter portion 49 to pass throughthe inner diameter of the lower bearings 109. Shaft 49 and circlet 108may be machined from a single piece of metal, or the circlet 108 may besubsequently attached to the shaft 49. They are preferably formed ofstainless steel. Further, an O ring 107 is provided adjacent the circlet108, on the thicker diameter portion 49 a of the shaft 49, to provide awater seal. Both the circlet 108 and the O ring have an outer diametersmaller than that of the upper bearing, so that they are not visible tothe user when in situ. However, the circlet has an outer diametersufficiently larger than the inner diameter of the upper bearing, so asto prevent the key from falling out of the device.

[0115] The key tips are crafted into the desired shape from a desiredmaterial, which may be a metal such as gold, platinum, silver, orstainless steel. They may also bear precious stones. For example a keytip or tips may be diamond encrusted, or have a precious stone set init. Once a key shaft has been passed through an upper bearing, a key tipis joined to it. This may be achieved using conventional braisingtechniques.

[0116] The spring plate supports 114 are provided on the PCB 118. Eachspring plate support 114 is preferably of unitary structure,manufactured from lightweight metal such as aluminium. The supports maythen be soldered onto the PCB using conventional techniques. The springplate supports 114 are positioned to hold the spring plates 110 so thatthe centres of their shaft apertures align with those of the lowerbearings 109. Contact regions for the spring plate contacts are providedon the PCB (or the lip of the second or fourth member of the support asdescribed above).

[0117] The spring plates 110 themselves are provided by stamping sheetmetal, such as beryllium cooper with gold flash or the like. The plates110 are affixed to the supports 114 by positioning one end 113 of thespring plate under the lip 116 of the second member of the support 114,fitting the other end 112 of the spring plate in the recess 115 of thefirst member of the support 114, flexing the tongue so that its endcorresponds to the recess 117 of the third member of the support 114,and positioning the end of the tongue in that recess. When in position,the free end 113 of the spring plate 110 is naturally biased upwardstoward the restraining lip 116.

[0118] The dimensions of various components of the keys and theirrelative positions are important in smooth key operation. The distancebetween the upper and lower bearings has been maximised by placing themeither side of the spring plate switching mechanism and passing theshaft through the spring plate. In such a position, the bearings holdthe key straight when it is operated, thereby avoiding contact withneighbouring key tips or the need to place keys further apart to preventsuch contact. This, in turn, results in good switching functionality andfeel.

[0119] Also, the dimensions of the keys are such that the lower surfaceof each key tip 64 contacts the surface of the Perspex layer 37 beforeexcess pressure can be applied to the spring plate 110. In the presentembodiment, the circlet 108 is positioned along the shaft such that itgently rests on the spring plate when the keys are in their normalnon-depressed state. Also, the thicker portion of the shaft is of anappropriate length that, when in the normal state, there is a gapbetween the lower surface of the key tips and the surface of the Perspexlayer 37 which is the same as, or only slightly greater than thedistance the circlet 108 has to travel to cause the spring platecontacts to contact the contact regions. This overcomes a potentialproblem of pressure being applied to the spring plate if the switchitself provides the end stop for the motion.

[0120] The dimensions of the keys are also important for the externalappearance of the device. Preferably, the key tips are of a thicknessthat they protrude from the surface of the second layer 51 of thecomposite, at least when the keys are in the aforementioned normalstate. When the composite is substantially transparent, this will givethe impression of floating keys, and add to the three dimensional effectmentioned earlier concerning the key legends 15. Furthermore, the keytips should be sufficiently deep to be partially sunk into the secondlayer of the composite, and preferably have at least two opposingsubstantially flat sides which correspond with sides of the second layerto prevent lateral rotation of the keys. A gap of the order of 0.1 mm isachieved in the present device between the keys and second layer of thecomposite: a gap insignificant to the human eye and suitable forassisting in the prevention of lateral rotation of the keys. Lateralrotation is further hindered in the present embodiment, by virtue of theprovision of mirrored slanting of the sides of adjacent keys.

[0121] In order to ensure the correct relative spacing of elements ofthe key, the Perspex layer 37, PCB 118, and titanium plate 77 areclamped together. In this embodiment, the clamping is provided by thefront face protectors 63, and by the provision of additional tappedbosses in projections 68 of the Perspex plate and associated fixingmeans. Consequently, once the keys have been positioned, the Perspexlayer, PCB and titanium plate can be clamped together using the bossesand fixing means, thereby holding the keys in place and forming amanageable module. This module may then be readily installed in thedevice using the front face protectors as described above with referenceto FIG. 9B.

[0122] Operation of the keys of the device will now be described. As theuser applies pressure to a key tip, the shaft moves downwards,travelling through the bearings and shaft aperture of the spring plate.This results in the circlet applying pressure to the part of the mainbody of the spring plate which defines the shaft aperture. Continuedpressure on the key tip will then cause the circlet to apply anincreasing force to this part of the spring plate, causing the main bodyto deform around the circlet. Eventually, this deformation will causethe tongue to overcentre, resulting in the free end 113 of the springplate 110 flicking from its naturally biased position (upwards towardsthe restraining lip 116) to a second position, in which the spring platecontacts contact the contact regions on the PCB. An electrical signal isconsequently sent to the processor indicative of actuation of that key.This arrangement gives a distinct click providing a clear qualityindication to the user that the key has been actuated. As the userremoves pressure from the key tip, the circlet, in turn, removespressure from the spring plate 110. The tongue promptly returns to itsnormal position, and the free end of the spring plate flicks up to itsnaturally biased position, breaking the contact.

[0123]FIG. 20a is a graph illustrating the force against distanceprofile for a key such as that illustrated in FIGS. 17 and 18. Thisprofile improves the tactility of the key over, for example, a typicalkeydome arrangement, which had a fairly flat profile as can be seen inFIG. 20b. When using a conventional key dome type arrangement, the userhas to apply a constant force until the point where the key actuates. Asa result, he does not get a tactile indication that he is nearing theposition when actuation is likely to occur. In contrast, when using thedevice illustrated in FIGS. 17 and 18, the user can realise the factthat he is nearing the position when actuation is likely to occur as heis having to increase the force applied for a given travel of the key.Furthermore, the user is informed when actuation takes place, and againwhen deactuation takes place, by respective clicking sounds provided bythe key.

[0124] The central V shaped key tips of the embodiment illustrated inFIG. 1 enable the user to determine the central vertical axis of thedevice both by sight and by touch. This is made even easier by thepillow 16 being provided with an apex. Consequently the user can quicklylocate a desired central key. The apexes of each central key tip alsoidentify the mid point along the length of the key tip, the point fromwhich the key shaft 49 extends. Hence, they facilitate more accuratedepression of the key. This, in turn, may assist in the prevention ofcontact with neighbouring key tips or the need to place keys furtherapart to prevent such contact.

[0125] Likewise, in this embodiment, the combination of adjacent outerkey tips and front face protectors forming a V shape enable the user todetermine the position of the vertical axes to one side of which theouter keys lie. Consequently, the user can quickly locate a desiredouter key. The key location process is facilitated in this embodiment asthe outer key tips extend to the interface between the second layer ofthe composite 51 and the bezel 19.

[0126] The front face of the device illustrated in FIG. 1 is protectedby the pillow and front face protectors, 63. The front face 3 isslightly convex, with the highest points lying along its centrallongitudinal axis. Hence, ordinarily, if placed face down, the devicewould rest on this axis, resulting in scratches to its surface. Clearly,this is not acceptable, particularly when the second layer of compositeis sapphire or the like. The device illustrated in FIG. 1 has beendesigned to avoid this problem. The pillow 16 and face protector 63 aprevent the device resting on the second layer of composite. Also, asmentioned above, in the preferred embodiment the key tips protrudeslightly from the surface. Hence, the central key tips too may protectthe second layer of composite from damage. However, preferably thepillow 16 and chin front face protector 63 a are raised sufficientlyabove the front surface, that the device does not rest on the centralkey tips either, so as to protect them from damage too.

[0127] The device is also designed so that the front face is protectedif the edge of the face is knocked. As can be seen from the plan view ofthe device, depicted in FIG. 21, the bezel front face protectors 63 bprotrude beyond the surface of the second layer of composite along theinterface with the bezel, thereby protecting the second layer ofcomposite from damage in that region. They also reduce the likelihood ofdamage to the bezel due to knocks. Moreover, they protrude further thanthe adjacent key tips, hence protecting those key tips from damage too.

[0128] One further benefit of the front face protectors 63, particularlythe bezel is that they are dimensioned so as to prevent the keys frombeing accidentally actuated if, for example, the device was placed facedown. That is, the top surface of the front face protector tips shouldeither be at the same level or higher than the top surface of a key tip(e.g. as in the relationship between the protectors 63 b and theadjacent outer key tips) or, if they are at a lower level than the topsurface of a key tip, the distance between the top surface of theprotector and key tips must be smaller than the distance the key needsto travel in order for the spring plate contacts to contact the PCBcontact region for actuation the key.

[0129] FIGS. 22 to 25 show alternative key and/or front face protectorconfigurations to those of the device of FIG. 1.

[0130]FIG. 22 shows an alternative key layout, which again utilises theinventive concept of using the keys as tactile markers. The shape of thekeys is similar to those of the alphanumeric key array of the deviceshown in FIG. 1, with one exception: the sides of the keys are alignedwith the longitudinal axis of the device.

[0131] In order to commission a casing for a portable communicationsdevice there will be a list of designated casing elements thecharacteristics of which are selectable by a commissioning party. Thislist of possible parts for personalisation may be provided in amongstother ways on a computer, on a web site or as a paper list in a suitablestore. The party commissioning the device can then select thecharacteristics of the designated elements from a set of possibleoptions provided. In alternative embodiments the scope for originalityin the characteristics of individual ones of the designated elements maybe greater and the commissioner may be given a practically free hand indetermining the material, and other additions such as surface decorationby etching or engraving and, amongst other things, encrustation.

[0132] The entire process could be computerised so that the selectedcharacters of the device are readily conveyed to a manufacturinglocation or location for realisation of the selected characters for thedesignated elements. This could be via an intermediary that records thecustomers specifications for later use and utilises the skills of arange of craftspersons to make the required elements and coordinates thecollocation of the individual elements for assembly. The device will bedescribed in greater detail below with exemplary materials being givenfor specific elements of the device. Where a material or veneer isdiscussed in relation to an element, the reader should be aware that theparticular character of the element described is one of many or severalthat may be provided as options to a party commissioning a personaliseddevice. In addition the exact material or surface decoration of theelement could be individually commissioned. As another option thespecification of the commissioner could be directly forwarded to alocation with the selected elements in stock for immediate assembly. Inthis embodiment either individually commissioned elements would not bepossible at all or restricted to a relatively small number of tasks thatcan be performed after the initial materials and finish of an elementhave been decided, such as engraving and possibly jewel encrustation.

[0133] For greater freedom in individually commissioned elements, theseelements could be individually designed and fabricated and finallyforwarded for assembly with the less unique elements. Should assembly ofthe elements require particular skills or for perhaps other reasons theassembly may occur at yet another location.

[0134] The formed article is then conveyed to the end user.

[0135] Aspects of the invention have been discussed with reference to aradio telephone function. It will be clear to the skilled man that theseaspects apply equally to other portable communications devicessupporting in addition or as an alternative other functions, such as,amongst others electronic diaries, and electronic notepads.

[0136] Also, the casing may be a conventional one part casing or a clamshell, or other two or more part arrangement, where the user inputelements or keys may be located on a different face to a display. Insuch two part arrangements generally respective casing portions arefixed such that one is movable relative to the other. The movement maybe rotational or lateral.

[0137] In the future, although the casing will probably be maintained insubstantially the same condition, the engine could be replaced with anengine that perhaps has greater processing power or allows for differentfunctionality, for example improved graphics. To replace the engine willbe a relatively simple manner of removing the existing engine andreplacing it with a new one. The battery and internal casing walls maybe changed at the same time if greater battery volume is then possible.

[0138] The present invention includes any novel feature or combinationof features disclosed herein either explicitly or any generalisationthereof irrespective of whether or not it relates to the claimedinvention or mitigates any or all of the problems addressed.

[0139] In view of the foregoing description it will be evident to aperson skilled in the art that various modifications may be made withinthe scope of the invention.

1. A portable communication device comprising a front face having aplurality of openings therein, and an array of keys, each key comprisinga switch actuator and a switching element, wherein each switch actuatorprotrudes from one of the plurality of openings to provide its uppersurface for tactile actuation by a user, and a coupler for coupling thetactile actuation of the upper surface by a user to the switchingelement, wherein the coupler comprises a shaft extending from the switchactuator and a first bearing around the shaft, the first bearingallowing for longitudinal movement of the switch actuator with respectto the first bearing and being a jewelled bearing.
 2. A device asclaimed in claim 1, wherein the coupling means comprises first andsecond bearings for supporting the shaft.
 3. A device as claimed inclaim 2, wherein the first and second bearings are spaced apart.
 4. Adevice as claimed in claim 3, wherein the shaft extends through theswitching element and the first bearing is located on one side of theswitching element, between the switch actuator and the switchingelement, and the second bearing is located on the other side.
 5. Adevice as claimed in any of preceding claim, wherein the first bearingis non-resilient.
 6. A device as claimed in any preceding claim, whereinthe first bearing comprises corundum gemstone.
 7. A device as claimed inany preceding claim, wherein the first bearing is a ruby bearing.
 8. Adevice as claimed in any of claims 2 to 7, wherein the second bearing isresilient.
 9. A device as claimed in claim 8, wherein the second bearingis a PFTE bearing. 10 A device as claimed in any preceding claim,wherein the switch actuator comprises a key tip for providing the uppersurface.
 11. A device as claimed in claim 10, wherein the key tipcomprises metal.
 12. A device as claimed in claim 10 or 11, wherein thekey tip comprises a precious material, such as gold, platinum, orsilver.
 13. A device as claimed in claim 12, wherein the key tipcomprises a jewel.
 14. A device as claimed in any preceding claimwherein the switch actuators are physically discrete.
 15. A device asclaimed in any preceding claim wherein the switching elements arephysically discrete.
 16. A device as claimed in any preceding claim,wherein the switching element comprises a contact and a mechanismresponsive to the coupling means for bringing the contact into and outof contact with a corresponding contact of the device.
 17. A device asclaimed in claim 16, wherein the switching element comprises a springplate.
 18. A device as claimed in claim 17, wherein the spring plate hasa fixed end and a free end, and a contact for contacting with acorresponding contact of the device, towards the free end.
 19. A deviceas claimed in claim 17, wherein the coupling means is arranged to couplethe tactile actuation of the upper surface by a user towards the fixedend of the spring plate.
 20. A device as claimed in claim 17, 18 or 19,wherein the spring plate comprises a flexed tongue between the fixed andfree ends.
 21. A device as claimed in any of claims 17 to 20, whereinthe array comprises a row of keys and the spring plates of first andsecond adjacent keys in the row are perpendicular to each other.
 22. Adevice as claimed in claim 21, wherein the spring plate of a third keyin the row, adjacent the second, is perpendicular to the second.
 23. Adevice as claimed in claim 22, wherein the spring plate of the third keyis parallel to, and in phase with, that of the first key.
 24. A deviceas claimed in any of claims 17 to 23, wherein the array comprises acolumn of keys and the spring plates of at least first and secondadjacent keys in the column are in parallel with each other.
 25. Adevice as claimed in claim 24, wherein the spring plates of first andsecond adjacent keys in the column are also in phase.
 26. A device asclaimed in any preceding claim, wherein the front face is substantiallytransparent.
 27. A device as claimed in claim 26, wherein the front facecomprises a precious material, such as sapphire.
 28. A device as claimedin any preceding claim, wherein the array comprises a row of keysprotruding through a single opening in the front face.
 29. A device asclaimed in any preceding claim, wherein the array comprises a pluralityof rows of keys, each row of keys protruding through a respective singleopening in the front face.
 30. A device as claimed in claim 29, whereinthe array of keys is a 3×4 array.
 31. A device as claimed in anypreceding claim, wherein the array of keys is an alphanumeric key array.32. A device as claimed in any preceding claim, wherein said pluralityof keys are arranged in at least one row extending laterally, whereinthe keys in the row are contiguous.
 33. A device as claimed in claim 32,wherein the contiguous keys protrude through a single V shaped openingin the front face.
 34. A device as claimed in claim 32 or 33, whereinthe contiguous keys extend right across the front face, from one side ofthe front face to the other.
 35. A device as claimed in claim 34,wherein the contiguous keys comprise a central key, a left key to theleft of the central key and a right key to the right of the central key,such that the central key is contiguous with the left and right keys,whereas the left key is contiguous with only the central key and theleft key is contiguous with only the central key.
 36. A device asclaimed in any preceding claim, wherein one of said plurality of keyshas a vertex, in the boundary of its upper surface, indicative of thelocation for tactile actuation.
 37. A device as claimed in claim 36 whendependent upon claim 35, wherein the central key is said one key havinga vertex in the boundary of its upper surface.
 38. A device as claimedin claim 36 or 37, wherein the vertex in the boundary of the at leastone of said keys is obtuse.
 39. A device as claimed in any precedingclaim, wherein the at least one of said keys has a boundary with asubstantially V shaped portion along one side.
 40. A device as claimedin any preceding claim, wherein the at least one of said keys has asubstantially V shaped boundary, with a first vertex in one side and asecond vertex in another side.
 41. A portable communication devicecomprising an array of keys having a switch actuator, a switchingelement and a jewelled bearing, substantially as hereinbefore describedand/or as illustrated in the accompanying drawings.